The existing research on dynamics and slip ratio of wheeled mobile robot （WMR） are derived without considering the effect of height, and the existing models can not be used to analyze the dynamics performance of the...The existing research on dynamics and slip ratio of wheeled mobile robot （WMR） are derived without considering the effect of height, and the existing models can not be used to analyze the dynamics performance of the robot with variable height while moving such as NOROS- Ⅱ. The existing method of dynamics modeling is improved by adding the constraint equation between perpendicular displacement of body and horizontal displacement of wheel into the constraint conditions. The dynamic model of NOROS- Ⅱ in wheel motion is built by the Lagrange method under nonholonomic constraints. The inverse dynamics is calculated in three different paths based on this model, and the results demonstrate that torques of hip pitching joints are inversely proportional to the height of robot. The relative error of calculated torques is less than 2% compared with that of ADAMS simulation, by which the validity of dynamic model is verified, Moreover, the relative horizontal motion between fore/hind wheels and body is produced when the height is changed, and thus the accurate slip ratio can not be obtained by the traditional equation. The improved slip ratio equations with the parameter of the vertical velocity of body are introduced for fore wheels and hind wheels respectively. Numerical simulations of slip ratios are conducted to reveal the effect of varied height on slip ratios of different wheels. The result shows that the slip ratios of fore/hind wheels become larger/smaller respectively as the height increases, and as the height is reduced, the reverse applies. The proposed research of dynamic model and slip ratio based on the robot height provides the effective method to analyze the dynamics of WMRs with varying height.展开更多
将气压测高方法应用于基于通信卫星的中国区域定位系统(Chinese Area Positioning System,CAPS)中,可以补充卫星星座、改善星座布局、提高定位精度。介绍了气压测高原理、高程约束定位解算模型和方法,在CAPS-I期系统中进行了仿真计算与...将气压测高方法应用于基于通信卫星的中国区域定位系统(Chinese Area Positioning System,CAPS)中,可以补充卫星星座、改善星座布局、提高定位精度。介绍了气压测高原理、高程约束定位解算模型和方法,在CAPS-I期系统中进行了仿真计算与分析,对高程约束下CAPS的定位精度情况以及气压测高自身误差对定位精度的影响进行了深入的研究和探讨,从而为气压测高下的实际定位工作提供了指导与参考。展开更多
基金supported by National Outstanding Youth Science Foundation of China (Grant No. 51125020)National Hi-tech Research and Development Program of China (863 Program, Grant No. 2006AA04Z207)Program for New Century Excellent Talents in University, China
文摘The existing research on dynamics and slip ratio of wheeled mobile robot （WMR） are derived without considering the effect of height, and the existing models can not be used to analyze the dynamics performance of the robot with variable height while moving such as NOROS- Ⅱ. The existing method of dynamics modeling is improved by adding the constraint equation between perpendicular displacement of body and horizontal displacement of wheel into the constraint conditions. The dynamic model of NOROS- Ⅱ in wheel motion is built by the Lagrange method under nonholonomic constraints. The inverse dynamics is calculated in three different paths based on this model, and the results demonstrate that torques of hip pitching joints are inversely proportional to the height of robot. The relative error of calculated torques is less than 2% compared with that of ADAMS simulation, by which the validity of dynamic model is verified, Moreover, the relative horizontal motion between fore/hind wheels and body is produced when the height is changed, and thus the accurate slip ratio can not be obtained by the traditional equation. The improved slip ratio equations with the parameter of the vertical velocity of body are introduced for fore wheels and hind wheels respectively. Numerical simulations of slip ratios are conducted to reveal the effect of varied height on slip ratios of different wheels. The result shows that the slip ratios of fore/hind wheels become larger/smaller respectively as the height increases, and as the height is reduced, the reverse applies. The proposed research of dynamic model and slip ratio based on the robot height provides the effective method to analyze the dynamics of WMRs with varying height.
文摘将气压测高方法应用于基于通信卫星的中国区域定位系统(Chinese Area Positioning System,CAPS)中,可以补充卫星星座、改善星座布局、提高定位精度。介绍了气压测高原理、高程约束定位解算模型和方法,在CAPS-I期系统中进行了仿真计算与分析,对高程约束下CAPS的定位精度情况以及气压测高自身误差对定位精度的影响进行了深入的研究和探讨,从而为气压测高下的实际定位工作提供了指导与参考。
